无限滚动列表视图 [英] endless scroll list view

问题描述

listView.setOnScrollListener(new OnScrollListener() {

                public void onScrollStateChanged(AbsListView view, int scrollState) {


                }

                public void onScroll(AbsListView view, int firstVisibleItem,
                        int visibleItemCount, int totalItemCount) {

                    if(loading){
                        //if trying to loading
                        if(totalItemCount > previousTotal){

                        loading = false;
                        previousTotal = totalItemCount;
                        }
                        }
                    if(!loading && ((totalItemCount - visibleItemCount) <= (firstVisibleItem + visibleThreshold))){

                        limit=limit+10;
                                    AlertSearchAsync task1=new AlertSearchAsync();
                            String url="http://www.jobdiagnosis.com/fjobsrchservise.php?keyword="+
                                    str_descAlert+
                                    "&location="+str_locAlert+
                                    "&limit="+limit;
                            url=url.replace(" ", "%20");
                            //Toast.makeText(getApplicationContext(),"Limit"+limit, Toast.LENGTH_LONG).show();
                            task1.execute(url);
                   }

            });

第一次异步类调用完美之后滚动一两个项目然后调用异步类并更新列表视图和顶部选择的列表视图

first time asyn class call perfect and after that when scroll one and two item then call asyn class and updated listview and list view selected at top

推荐答案

试试这个，

public abstract class EndlessScrollListener implements OnScrollListener {
// The minimum amount of items to have below your current scroll position
// before loading more.
private int visibleThreshold = 1;
// The current offset index of data you have loaded
private int currentPage = 0;
// The total number of items in the dataset after the last load
private int previousTotalItemCount = 0;
// True if we are still waiting for the last set of data to load.
private boolean loading = true;
// Sets the starting page index
private int startingPageIndex = 0;

public EndlessScrollListener() {
}

public EndlessScrollListener(int visibleThreshold) {
    this.visibleThreshold = visibleThreshold;
}

public EndlessScrollListener(int visibleThreshold, int startPage) {
    this.visibleThreshold = visibleThreshold;
    this.startingPageIndex = startPage;
    this.currentPage = startPage;
}

// This happens many times a second during a scroll, so be wary of the code
// you place here.
// We are given a few useful parameters to help us work out if we need to
// load some more data,
// but first we check if we are waiting for the previous load to finish.
@Override
public void onScroll(AbsListView view, int firstVisibleItem,
        int visibleItemCount, int totalItemCount) {
    // If the total item count is zero and the previous isn't, assume the
    // list is invalidated and should be reset back to initial state
    // If there are no items in the list, assume that initial items are
    // loading
    if (!loading && (totalItemCount < previousTotalItemCount)) {
        this.currentPage = this.startingPageIndex;
        this.previousTotalItemCount = totalItemCount;
        if (totalItemCount == 0) {
            this.loading = true;
        }
    }

    // If it’s still loading, we check to see if the dataset count has
    // changed, if so we conclude it has finished loading and update the
    // current page
    // number and total item count.
    if (loading) {
        if (totalItemCount > previousTotalItemCount) {
            loading = false;
            previousTotalItemCount = totalItemCount;
            currentPage++;
        }
    }

    // If it isn’t currently loading, we check to see if we have breached
    // the visibleThreshold and need to reload more data.
    // If we do need to reload some more data, we execute onLoadMore to
    // fetch the data.
    if (!loading
            && (totalItemCount - visibleItemCount) <= (firstVisibleItem + visibleThreshold)) {
        onLoadMore(currentPage + 1, totalItemCount);
        loading = true;
    }
}

// Defines the process for actually loading more data based on page
public abstract void onLoadMore(int page, int totalItemsCount);

@Override
public void onScrollStateChanged(AbsListView view, int scrollState) {
    // Don't take any action on changed
}
}

使用上面的类.然后像这样将你的 listView 实现到 EndlessScrollListener

Use the above class. and just implement your listView to EndlessScrollListener like this

list.setOnScrollListener(new EndlessScrollListener() {

        @Override
        public void onLoadMore(int page, int totalItemsCount) {
            // TODO Auto-generated method stub
            new Loadmore().execute();

        }
    });

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